The imminent completion of the series long-gestation papers on flash pacemaking in New Guinea fireflies was again interrupted by the principal investigator's inability to resist an invitation to write an overview chapter for a symposial monograph on bioluminescence. The choice of subject -- function and evolution of bioluminescence -- was very educational because it required critical review and rethinking of a large corpus of literature, primarily on marine animals, and an attempt to view the question of the origin and development of the polyphyletic ability to emit light in the light of modern concepts of molecular biology. With regard to the pacemaker work, Dr. Hanson completed a computerized retrieval program by means of which we processes several thousand feet of tape-recorded data that had previously either not been analysed at all or only fragments. Mrs. Buck has analysed most of the field data (two and three channel synchrony) among these records. BIBLIOGRAPHIC REFERENCE: Hanna, C. H., Hopkins, T. A. and Buck, J.: Peroxisomes of the firefly lantern. J. Ultrastructure Res. 57: 150-162, 1976, In press.